The RFA specifically requests that the applicants confirm their interest and ability to take part in clinical treatment trials in Intersitial Cystitis (IC). The Queen's University Intersitial Cystitis Research Group is established under the directorship of Dr. J. Curtis Nickel in Kingston, Canada and recently expanded to take part in the NIH ICCTG RCT #2. The Queen's University Intersitial Cystitis Research Group has enrolled 255 patients in 12 clinical trials, specifically in clinical IC treatment studies (this does not include the many patients recruited for etiology and diagnostic studies during the same time period). As part of the NIH ICCTG, the Queen's University site has exceeded its enrollment quota to date for RCT #2.. The interstitial cystitis research group is closely affiliated with the Queen's University Prostatitis Research Group (PI Dr. J.C. Nickel) which is collaborating in the NIH CPCRN (including CPCRN RCT#1). The Prostatitis research center is also meeting its recruitment quota in RCT#1. To our knowledge the Queen's University Prostatitis Research Center has initiated more prostatitis treatment trials and has enrolled more patients than any such research group worldwide. This application describes our aim to participate in the proposed NIH ICCRN as well as the proposed urological chronic pelvic pain syndromes collaborative group (UCPPSCG). Our group is proposing a clinically relevant definition of the urologic chronic pelvic pain syndromes encompassing both IC and male CPPS. This definition, based on chronic genito-urinary pain/discomfort with subcategories for urinary frequency urgency and no urinary frequency urgency will, if adopted by the UCPPSCG, facilitate decisions on treatments to be evaluated and increase the accrual rate of study participants in both IC and CPPS. We develop a rationale, hypothesis, objectives necessary to propose a 16 week randomized placebo controlled clinical trial (employing 2X2 factorial design) to evaluate the efficacy and safety of amitriptyline and gabapentin for the amelioration of symptoms in patients with a clinical diagnosis of IC. The Queen's University. site with Dr. Nickel as PI has the experience, expertise and the proven ability to design, implement and enroll patients with IC in clinical strudies and will be a valuable partner in the proposed ICCRN and UCPPSCG.